APA Format
Ahern, Cecelia. (2004).
PS : love you / Cecelia Ahern
. New York :: Hyperion ,.
MLA Format
Ahern, Cecelia.
PS : love you / Cecelia Ahern
. New York :: Hyperion ,, 2004
Chicago Format
Ahern, Cecelia. PS : love you / Cecelia Ahern. New York :: Hyperion ,, 2004.